1. Field of the Invention
The present invention relates to shed-forming devices n a weaving loom which includes a plurality of systems for opening and closing the shed. Each system comprises movable hooks made of plastic material which move vertically in reciprocating manner, as well as two hooks for retaining the movable hooks and an electro-magnet. Each of the movable hooks is provided with a tongue cooperating with the corresponding retaining hook with a view to effecting what is called "levelling" in the art. This operation consists in pivoting the retaining hook by means of the tongue of the movable hook in order to urge the retaining hook against the pole piece of an electromagnet.
2. History of the Related Art
Applicants U.S. Pat. No. 4,739,806 discloses a device of the type in question, of which the movable hooks are made of an appropriate plastics material giving the levelling tongue the ability to flex. However, being given that this tongue is subjected to very considerable stresses of friction and deformation, even with the use of high-performance materials, there are risks of permanent deformation or of creeping of the tongue, of which the mechanical properties are thus altered. A loss of the elasticity of the tongue brings about defects in levelling which lead to defects in weaving.
The improvements forming the subject matter of the present invention aim at overcoming these drawbacks and at producing a tongue which does not lose its elasticity.